Senate Majority Leader Mitch McConnell (R-Ky.) spent nearly a year blocking President Barack Obama's nominee for he vacant Supreme Court nominee — one of the longest vacancies on the court in the nation's history.

But now, McConnell is calling Democrats out for vowing to block President-elect Donald Trump's eventual nominee if his pick doesn't meet their standards, leading Twitter to call him out for playing politics.

McConnell: "The American people simply will not tolerate" Democrats blocking Trump's SCOTUS nominee

"That's something the American people simply will not tolerate, and we'll be looking forward to receiving a Supreme Court nomination and moving forward on it," McConnell said.

The Republicans will need 60 votes in order to bring Trump's eventual nominee to the floor. With only 52 seats, that means the Republicans need eight Democrats to switch to their side — a large hurdle to overcome.

McConnell's comments come after a day after Senate Minority Leader Chuck Schumer told MSNBC the Supreme Court vacancy was "stolen" from Obama, and that Democrats would not vote to confirm a Trump nominee who met their standards.

"It's hard for me to imagine a nominee that Donald Trump would choose that would get Republican support that we could support," Schumer said Tuesday.

Schumer vows to oppose any "out of the mainstream" SCOTUS nominee. Doesn't define "mainstream" or say if any in Trump's list of 21 qualify.

Twitter users called out McConnell for acting shocked and appalled that Democrats would seek to block a Trump nominee, after he refused to give Obama's nominee Merrick Garland a hearing.

I don't want to alarm anyone, but I'm starting to suspect that politicians may sometimes behave in a hypocritical manner https://t.co/lC04b0vmx2

Trump lost the popular vote, so shouldn't Clinton pick the SCOTUS nominee to reflect the American people's voices be heard? https://t.co/dLgz6XMo03

Trump has yet to nominate someone to fill the vacancy left when Justice Antonin Scalia died in February.

But he released a list of 21 possibilities, a who's who of conservative justices.